/* eslint-disable */
(function(win) {

    var doc = win.document,
        docEl = doc.documentElement,
        metaEl = doc.querySelector('meta[name="viewport"]'),
        dpr = 0,
        scale = 0,
        name = '',
        timer = null;
    if (metaEl) {
        var match = metaEl.getAttribute('content').match(/initial\-scale=([\d\.]+)/);
        if (match) {
            scale = parseFloat(match[1]);
            dpr = parseInt(1 / scale);
        }
    }
    var UA = win.navigator.appVersion,
        isIPhone = UA.match(/iphone/gi),
        isAndroid = UA.match(/android/gi),
        isApp = UA.match(/NewsApp/gi),
        isPc = UA.match(/Windows/gi) || UA.match(/Macintosh/gi);
    if (!dpr && !scale) {
        var devicePixelRatio = win.devicePixelRatio;
        if (isIPhone) {
            // iOS下，对于2和3的屏，用2倍的方案，其余的用1倍方案
            if (devicePixelRatio >= 3 && (!dpr || dpr >= 3)) {
                dpr = 3;
            } else if (devicePixelRatio >= 2 && (!dpr || dpr >= 2)) {
                dpr = 2;
            } else {
                dpr = 1;
            }
        } else {
            // 其他设备下，仍旧使用1倍的方案
            dpr = 1;
        }
        scale = 1 / dpr;
    }
    docEl.setAttribute('data-dpr', dpr)
    // console.log(dpr)

    if (!metaEl) {
        metaEl = doc.createElement('meta');
        metaEl.setAttribute('name', 'viewport');
        metaEl.setAttribute('content', 'initial-scale=' + scale + ', maximum-scale=' + scale + ', minimum-scale=' + scale + ', user-scalable=no');
        if (docEl.firstElementChild) {
            docEl.firstElementChild.appendChild(metaEl);
        } else {
            var wrap = doc.createElement('div');
            wrap.appendChild(metaEl);
            doc.write(wrap.innerHTML);
        }
    }

    function refreshRem() {
        var width = docEl.getBoundingClientRect().width;
        if (width / dpr > 540) {
            width = 540 * dpr;
        }
        var rem = width / 10;
        docEl.style.fontSize = rem + 'px';
        win.rem = rem
    }
    win.addEventListener('resize', function() {
        clearTimeout(timer);
        timer = setTimeout(refreshRem, 300);
    }, false);
    win.addEventListener('pageshow', function(e) {
        if (e.persisted) {
            clearTimeout(timer)
            timer = setTimeout(refreshRem, 300);
        }
    }, false)
    if (doc.readyState === 'complete') {
        doc.body.style.fontSize = 12 * dpr + 'px';
    } else {
        doc.addEventListener('DOMContentLoaded', function(e) {
            doc.body.style.fontSize = 12 * dpr + 'px';
        }, false);
    }

    refreshRem();

    win.px2rem = function(d) {
        var val = parseFloat(d) / win.rem
        if (typeof d === 'string' && d.match(/px$/)) {
            val += 'rem';
        }
        return val;
    }
    win.rem2px = function(d) {
        var val = parseFloat(d) * win.rem;
        if (typeof d === 'string' && d.match(/rem$/)) {
            val += 'px';
        }
        return val;
    }
})(window);
